Non-correcting lens blank, and method for making same

ABSTRACT

A nonconnecting lens blank and method provide an integrated optical function insert and allow for ease in trimming by the ability to visually orient the geometric alignment of the optical function insert. The nonconnecting lens blank has an inner concave face ( 2   c ) and an outer convex face ( 2   b ) delimited by a peripheral border ( 2   a ). A matrix ( 4 ) of transparent material transmits light from the outer face towards the inner face. An insert ( 6 ) integrating the optical function is placed in one of the faces of the matrix. The matrix may include a housing ( 5 ) in which the insert ( 6 ) is fitted. The insert ( 6 ) preferably has two truncated concentric circular edges ( 5   a   1, 5   a   2 ) separated by two straight parallel edges ( 5   a   3, 5   a   4 ). The optical function may be polarization with the plane of polarization aligned relative to the straight edges.

The present invention relates to noncorrecting lens blanks, which makeit possible to obtain noncorrecting lenses by trimming, and the shapeand dimensions of which are matched for mounting in or on a suitableframe of a pair of glasses.

The invention also relates to pairs of glasses, intended for solar orindustrial protection, comprising two noncorrecting lenses, each onecapable of being obtained by trimming a blank as defined above, theselenses being mounted or supported in or by a suitable frame.

More specifically, the invention relates to noncorrecting lens blankswhich are polarizing or which have another optical function and toglasses obtained from such blanks, and consequently, comprising twononcorrecting lenses which are also polarizing or which have this otherfunction. The latter is, for example, the photochromic function whichalters the intensity of the color of the glass according to theintensity of the light received. It is possible also to envision havingan infrared filter, or any other function.

At present, in order to obtain a polarizing noncorrecting lens blank,the starting material used is a composite sheet comprising a filteringfilm made of a polarizing material, inserted between two layers of alight-transmitting transparent material, preferably made of athermoplastic, for example a polycarbonate. Next, a strip delimited by aperipheral border is flat cut in this composite sheet. Then this stripis thermoformed in order to obtain a blank, according to anypredetermined radius of curvature, and delimited between one outerconvex face and an opposite inner and concave face. On the basis of thepreferred plane of polarization of the filtering film, and given theangular orientation of said film with respect to the two layers of thetransparent material, the blank acquires a preferred plane ofpolarization. The latter preferably remains substantially parallel tothe optical axis of the lens which will then be obtained by trimmingsaid blank.

The blanks and lenses obtained from composite thermoformed sheets havemediocre, even inadequate, optical characteristics, in particular forlarge curvatures (base 6 and above). This is because the power and prismvalues of the lens obtained by trimming such a blank do not comply withcurrent standards. This results especially from the fact that thethermoforming operation does not allow control of the relative positionof the anterior and posterior diopters, and therefore the position ofthe optical center of the blank.

Moreover, document FR 2 740 231 describes and proposes a noncorrectinglens blank having good optical properties, in particular power and prismproperties, including for glasses of strong curvature corresponding to amean radius of curvature at the most equal to about 90 mm. This blankcomprises a transparent strip having, on the one hand, a geometric axispassing through said strip and defining a geometric center, and, on theother hand, an optical axis defining an optical center. In addition, thestrip, seen in elevation, has a generally noncircular perimeter, and theoptical axis and the geometric axis and consequently the optical andgeometric centers, are distinct and offset at an angle and by apredetermined distance one from the other.

The subject of the present invention is a noncorrecting lens blankintegrating any optical function such as, for example, polarization,making it possible to obtain substantially the same opticalcharacteristics as those obtained according to document FR 2 740 231,notwithstanding the presence of a film in the blank allowing the latterto integrate a function such as polarization, infrared filtration or anyother known function that can be applied to a lens.

According to the present invention, the blank comprises a compositestrip, delimited by a peripheral border and between an outer convex faceand an opposite inner concave face, said composite strip consisting ofat least one transparent material, transmitting light from the outerface to the inner face, and said composite strip incorporating a filmintegrating the optical function. This composite strip has, in a firstembodiment according to the invention, the following structure andarrangement:

firstly, the strip comprises a matrix of transparent materialdetermining the inner face of the lens from the inner side; and in thismatrix from the outer side, a convex housing is reserved, whose flatsurface occupies the majority of the surface of the composite strip; and

a piece of film, matched in shape and in dimensions to the convexhousing, occupies the latter.

This composite strip has, in a second embodiment according to theinvention, the following structure and arrangement:

firstly, the strip comprises a matrix of transparent material,determining the outer face of the lens from the outer side; and in thismatrix, from the inner side, is reserved a concave housing whose flatsurface occupies the majority of the surface of the composite strip; and

a piece of film, matched in shape and in dimensions to the concavehousing, occupies the latter.

A blank obtained according to the invention makes it possible tocontrol, especially in terms of tolerance and positioning, the properorientation of this blank during its trimming, and consequently thequality of the lens thus obtained.

The housing is, for example, a convex housing placed on the outer faceof the matrix. By virtue of the arrangement of the film on the outerside of the blank, the outer face of the film corresponds mainly to theouter convex face of the blank, or subsequently of the lens. Inaddition, the stresses generated in the injected transparent material,which usually generate an unwanted polarization, are virtuallyimperceptible to the eye of the user of the glasses.

Advantageously, the piece of film has a constant thickness.

By way of first example, the peripheral border comprises two truncatedconcentric circular edges, separated by two straight parallel edges, forexample of identical length, and the perimeter of the housing hassubstantially the same profile as that of the peripheral border, and isfitted in a homothetic manner in the latter.

By way of second example, the peripheral border is at leastpredominantly circular, and the perimeter of the housing comprises twotruncated concentric circular edges, separated by two parallel straightedges, for example of identical length. In this example, the peripheralborder comprises, for example, a predominant circular part and astraight part, which is coincident with a straight edge of the housing.

In one embodiment, the inner and outer faces each have, at least inpart, a symmetry of revolution about the same axis, called the opticalaxis, determining, if required, an optical center on the two outer andinner faces of the composite strip. In this case, the peripheral borderhas, for example, at least in part, a profile of revolution about ageometric center, placed at a distance and distinct from the opticalaxis.

The outer face of the composite strip is advantageously coated by atleast one layer of a material chosen from the group comprisingscratch-resistant materials, filtering materials and colored materials.

The film integrating the optical function may be a filtering film of apolarizing material and the angular orientation of the piece offiltering film in and with respect to the matrix of transparentmaterial, about a normal axis passing through them, is then preferablychosen in order to give the blank a preferred plane of polarization,substantially parallel to a transverse plane intersecting it.

According to the invention, the preferred plane of polarization of thelense is chosen in order to exhibit any predetermined angularorientation (substantially perpendicular, parallel or other), withreference to an indicator or indicators usually present on the blank, inparticular taking account of the interface existing between polarizingand transparent materials, or with reference to an indicator orindicators recorded on the blank, for example hollow or relief marks,making it possible to define one or more reference axes at the time oftrimming.

By “substantially parallel or perpendicular”, the way in which thecurvature of the blank, and subsequently of the lens, considered in avertical or horizontal insertion plane (with respect to the lens inposition on the user's head, via glasses) deviates the orientation ofthe plane of polarization, going from the edge toward the center of theblank or of the lens, is taken into consideration.

A blank with a piece of polarizing filtering film, obtained according tothe invention, makes it possible to control the angular positioning ofthe preferred plane of polarization of the blank, especially in terms oftolerance, and then the lens obtained by trimming this blank.

For the first example above, that is to say when the peripheral bordercomprises two truncated concentric circular edges, separated by twostraight parallel edges, for example of identical length, and when theperimeter of the convex housing has substantially the same profile asthat of the peripheral border, and is fitted in a homothetic manner inthe latter and when the piece of film is a piece of polarizing filteringfilm, then the piece of filtering film is advantageously cut in thepolarizing film, so that the preferred plane of polarization issubstantially parallel or perpendicular to each straight parallel edgeof said piece, in view of which each straight parallel edge of the blankis substantially parallel or perpendicular to the preferred plane ofpolarization of the latter.

For the second example above, that is to say when the peripheral borderis at least for the most part circular, and the perimeter of the convexhousing comprises two truncated concentric circular edges separated bytwo straight parallel edges, for example of identical length, and whenthe piece of film is a piece of polarizing filtering film, then thepiece of filtering film is advantageously cut in band shape in thepolarizing film, such that the preferred plane of polarization issubstantially parallel or perpendicular to each straight parallel edgeof said piece, in view of which at least one straight line of separationbetween the matrix of the transparent material and the piece offiltering material is substantially parallel or perpendicular to thepreferred plane of polarization of the blank.

These arrangements allow an immediate visualization of the plane ofpolarization of the blank, which allows the glasses manufacturers totrim said blank in order to keep the plane of polarization of the lenssubstantially parallel or perpendicular to the visual axis of theglasses in position on the user's head.

When each of the inner and outer faces have, at least in part, asymmetry of revolution about the same axis, called the optical axis,determining an optical center on the outer and inner faces of thecomposite strip, if required, the optical axis is, for example,substantially parallel or perpendicular to the preferred plane ofpolarization of said blank for polarizing lenses. The geometric shape ofthe outer face and/or of the inner face of the composite strip, can alsobe determined such that in a plane of section substantially parallel orperpendicular to the preferred plane of polarization, the thickness ofthe composite strip decreases continually when moving away from theoptical axis toward the outside. In the latter case, the geometric shapeof the outer face and the geometric shape of the inner face correspond,for example, respectively to two spheres with centers spaced out alongthe optical axis.

When the peripheral border has, for example, at least in part, a profileof revolution about a geometric centre, placed at a distance anddistinct from the optical axis, the optical axis and the geometriccenter advantageously determine a plane substantially parallel orperpendicular to the preferred plane of polarization of said blank forpolarizing lenses.

The invention also relates to a pair of glasses comprising a frame andtwo noncorrecting lenses integrating an optical function such as, forexample, polarization, supported by said frame, each lens comprising acomposite strip delimited between an outer convex face and an oppositeinner concave face, said composite strip consisting of at least onetransparent material transmitting light from the outer face to the innerface, and said composite strip incorporating a film integrating theoptical function. According to the invention, each lens comprises, fromthe inside toward the outside or conversely, a first thickness oftransparent material, determining from the inner, outer side,respectively, said inner, outer face, respectively, and directly incontact with the first thickness, a second thickness of film,determining from the outer, inner side, respectively, said outer, innerface, respectively, of the lens.

When each lens of the pair of glasses is a polarizing lens, each lensis, for example, oriented at an angle with respect to the frame, about anormal axis passing through it, such that its preferred plane ofpolarization is substantially parallel or perpendicular to thehorizontal plane of the pair of glasses, passing through the visual axisof the glasses in position on the user's head.

The transparent material of a blank according to the invention can beobtained, for example by injection molding. The invention thus alsorelates to a mold for injecting the transparent material, consisting ofa thermoplastic or thermosetting synthetic material, in order to obtaina blank as described above, said mold comprising two complementary partswhich can be moved one with respect to the other, and which, onceassembled one on the other, determine a gap whose volume and shapedetermine those of the strip; the part of the mold determining the outerface of the strip comprises means for positioning the convex piece ofthe film. Such a mold will especially be used for polarizing blanks.

A blank according to the invention can also be obtained by a productionprocess comprising a step of overmolding the piece of film by extrusion.In this case, the pieces obtained after extrusion can be cut andthermoformed.

Another process of production means that the matrix of transparentmaterial and the piece integrating the function are produced separatelyand in [sic] that these two components are subsequently adhesivelybonded.

All these solutions make it possible to obtain a good optical quality,complying with the Gullstrand law.

The present invention is now described with reference to the appendeddrawings, in which:

FIGS. 1 and 2 show a blank according to the present invention, viewedrespectively from the outer side and from the inner side where the eyeof the user of the pair of glasses is then located, incorporating a lensobtained by trimming the blank according to FIGS. 1 and 2;

FIG. 3 shows a view in cross section of the blank according to FIGS. 1and 2, the plane of the section being horizontal with respect to thenormal position of the aforementioned pair of glasses on the user'shead, and passing through the optical center of the blank;

FIG. 4 shows, on an enlarged scale, a detail of FIG. 3;

FIG. 5 shows a pair of glasses comprising two lenses, each obtained bytrimming a blank according to FIGS. 1 to 4;

FIG. 6 shows a partial view in transverse section, along a horizontalplane as defined above, of the part of the glasses shown in FIG. 5,corresponding to the left lens;

FIG. 7 shows, in transverse section, an injection mold for a transparentthermoplastic material, for example polycarbonate, making it possible toobtain a blank according to the representation of FIGS. 1 to 4;

FIG. 8 shows, viewed end-on, a part of the mold shown in FIG. 7;

FIGS. 9 and 10 show, in a manner identical to the representation of FIG.2, two other embodiments of the present invention.

FIGS. 1 to 4 show a polarizing noncorrecting lens blank according to thepresent invention, which corresponds, after trimming, to a left lens ofa pair of glasses as shown in FIG. 5.

Generally, this blank 1 comprises a composite strip 2, having a curvedor convex shape. This strip is delimited by a peripheral border 2 a, andbetween an outer convex face 2 b and an opposite inner and concave face2 c. Mainly, this composite strip 2 consists of a transparent material,for example polycarbonate, transmitting light from the outer face 2 b tothe inner face 2 c of the strip. In addition, this strip incorporates afiltering film 6 of a polarizing material, which gives the blank apreferred plane of polarization 3.

The composite strip 2 comprises a matrix 4 of transparent material,completely determining from the inner side the inner face 2 c of theblank, and in which is reserved, from the outer side, a housing 5 ofconvex shape, the flat surface of which occupies the major part, if notalmost all of the surface of the composite strip 2. A piece 6 of afiltering film of a thermoplastic polarizing material is matched by flatcutting, then by thermoforming, to the convex shape and to thedimensions of the convex housing 5. The convexity of the housing 5 isidentical to that of the outer face 2 c of the matrix 4. This piece 6,after molding as described below, completely occupies the housing 5,virtually without space or interstice between the piece 6 and the matrix4, that is subsequently perceptible to the eye of the user of the futurelens. The angular orientation of the piece 6 of filtering film, in andwith respect to the matrix 4 of transparent material, about the samenormal axis passing through the matrix 4 and the piece 6, is chosen togive the blank, in a predetermined manner, a preferred plane ofpolarization 3, which will be discussed below.

The positioning of the piece 6 with respect to the matrix 4 is obtainedby any suitable means, for example by simple fitting or assembly, orwith hollow or relief indicators.

The piece 6 of the filtering film has a constant thickness, as shown inparticular in FIGS. 3 and 4, while the matrix 4 has a thicknessdecreasing from the optical axis toward the outside (FIG. 4).

The peripheral border 2 a of the blank 1 comprises two truncatedcircular edges 2 a 1 and 2 a 2, which are concentric about a geometriccenter or gravity center 10, and separated by two straight paralleledges 2 a 3 and 2 a 4, for example of identical lengths. As shown byFIGS. 1 and 2, the perimeter 5 a of the flat housing 5 has substantiallythe same profile as that of the peripheral border 2 a of the strip 2,and is fitted in a homothetic manner therein.

The piece 6 of filtering film is cut and thermoformed in the latter,such that the preferred plane of polarization of said film issubstantially parallel or perpendicular to each parallel straight edge 5a 3 or 5 a 4 of this piece, in view of which each parallel straight edge2 a 3 or 2 a 4 of the blank it itself substantially parallel orperpendicular to the preferred plane of polarization 3 of the latter(cf. in particular FIG. 2).

In a manner known per se, and in particular with reference to documentFR-2 740 231, the inner 2 b and outer 2 c faces of the composite strip 2each have, at least in part, a symmetry of revolution about the sameaxis 7 identical to the optical axis of the blank 1, determining anoptical center 8 on the outer 2 b and inner 2 c faces of the strip 2. Itmust be understood that the optical axis 7 does not necessarily passthrough the blank 1, and may be located outside the latter. As shown inFIG. 2, the optical axis 7 is substantially parallel to the preferredplane of polarization 3 of the blank 1.

Still in a manner known by document FR2 740 231, the geometric shape ofthe outer face 2 b and/or of the inner face 2 c of the composite strip2, are determined so that in a plane of horizontal section, as definedby reference to FIG. 3, itself substantially parallel to the preferredplane of polarization 3, the thickness of the composite strip 2decreases continually on moving away from the optical axis 7, that is tosay on going from the optical axis for example toward the outer leftside of the temple of the user of the glasses.

Preferably, and as shown in FIG. 3, the geometric shape of the outerface 2 b and the geometric shape of the inner face 2 c are fittedrespectively into two spheres with spaced-apart centers, the respectivecenters 81 and 9 of which are both located and offset one with respectto the other, on the optical axis 7. The radii R1 of the spherecorresponding to the outer face 2 b, and R2 of the sphere correspondingto the inner face 2 c, are different.

According to FIGS. 1 and 2, the result of the profile retained for theperipheral edge 2 a of the blank 1, is that the latter has, at least inpart, a profile of revolution about a geometric centre 10, which isplaced at a distance and distinct from the optical axis 7 and from theoptical center 8. Consequently, the optical axis 7 and the geometriccentre 10 determine a plane substantially parallel to the preferredplane of polarization 3 of the blank, as shown in FIG. 2 in particular.

According to the above definition of the expression “substantiallyparallel or perpendicular”, along the point in question on the blank,the preferred plane of polarization is in fact slightly secant orinclined (from 0° to 30°), with respect to the plane determined by theoptical axis 7 and the geometric centre 10.

By way of second embodiment, and according to FIG. 9, the peripheralborder 2 a of the lens 1 is circular, and the perimeter 5 a of thehousing 5 of the piece 6 of filtering film comprises two truncatedconcentric circular edges 5 a 1 and 5 a 2, separated by two parallelstraight edges 5 a 3 and 5 a 4, for example of identical lengths. Thepiece 6 of filtering film is cut in band shape in the polarizing film,such that the preferred plane of polarization 3 is substantiallyparallel or perpendicular to each straight edge of said piece, in viewof which each straight line of separation between the matrix 4 of thetransparent material and the piece 6 of filtering and colored materialis substantially parallel or perpendicular to the preferred plane ofpolarization 3 of the blank.

The blank shown in FIG. 10 differs from that shown in FIG. 9, in thatthe peripheral border 2 a comprises a predominantly circular part and astraight part 2 a 5, which is coincident with a straight edge 5 a 4 ofthe convex housing 5.

It must be understood that according to all the examples describedabove, the preferred plane of polarization 3 can be substantially, or[sic] parallel or perpendicular to the visual referential frame chosenand determined on the blank, for example the parallel straight edges 5 a3 and 5 a 4 according to FIG. 9.

Using a blank as defined above, it is possible to obtain by trimming,for example, a left lens 13, in order to mount it in a pair of glasses11, conventionally comprising a supporting frame 12 and the polarizingnoncorrecting right lens 13 and left lens 14. The pair of glasses 11 mayhave a particularly enveloping shape, by closely following over itssides the curvature of the user's forehead, which then leads to lenseswith a relatively low radius of curvature. As is shown in FIG. 6,starting from trimming and mounting, each lens 13 or 14 then comprises acomposite strip 15 delimited between a convex outer face 15 a and anopposite concave inner face 15 b. This composite strip 15 consists of atleast one transparent material 16, transmitting light from the outerface 15 a to the inner face 15 b. In addition, this composite strip 15incorporates a filtering film 17 of polarizing material, determining foreach lens at least one preferred plane of polarization 3 (cf. FIG. 5).

Each lens 13 or 14 comprises, from the inside toward the outside, on theone hand, a first thickness of transparent material 16, determining fromthe inner side the inner face 15 b, and on the other hand, directly incontact with the first thickness, a second thickness of the filteringfilm 17, determining from the outer side said outer face 15 a of thelens.

As is shown in FIG. 5, each lens 13 or 14 is oriented at an angle withrespect to the frame 12, about its optical axis 7 for example, such thatits preferred plane of polarization 3 is substantially parallel orcoincident with the horizontal plane of the pair of glasses, passingthrough the visual axis 18 of the glasses in position on the user'shead.

The term “visual axis” refers to an axis lying in a horizontal planepassing through the two pupils of the user, in front of the head of thelatter, and virtually without horizontal and/or vertical deviation froma point located at the center of the interpupillary separation.

As mentioned above for the blank 1, it must be understood that thepreferred plane of polarization 3 of each lens 13 or 14 is substantiallyor [sic] parallel or perpendicular to the frame of reference chosen andpredetermined on the pair of glasses 11, for example the horizontalplane passing through the visual axis 18.

FIGS. 7 and 8 show a mold 19 for injecting transparent material, forexample polycarbonate, in order to obtain a blank 1 as described above.This mold comprises two detachable parts 20 and 21 which arecomplementary to each other, determining, once assembled one on theother, a gap 22 whose volume and shape determine those of the strip 2.

According to the invention, the concave part of the mold 21 determiningthe outer face 2 b of the blank 1 comprises flat means or studs 23 a to23 c for positioning the convex piece 6 of filtering film.

The piece 6 can be cut flat, and not thermoformed. It is then placed andpositioned as above in the concave part 21 of the mold, temporarilyclosely matching its shape. It takes a final convex shape on injectionof the transparent material, for example polycarbonate.

According to one embodiment, the piece 6 of filtering film is cut flatthen thermoformed, in order to have in its curved form the shape and thedimensions described with reference to FIGS. 1 to 4. This piece is thenplaced in the gap 22 of the mold in order to act as an insert, by beingpositioned using the studs 23 a to 23 c, in order to define, afterinjection of the transparent material into the gap 22, a predeterminedorientation of the piece 6 with respect to the rest of the strip 2,giving the blank 1 a preferred plane of polarization, itself in anangular position determined with respect to the latter.

By virtue of the present invention, it is possible to trim each blank ina geometrically accurate manner with respect to its preferred plane ofpolarization, from which it follows that the lens thus obtained can bemounted in its turn in a geometrically accurate manner on the glassesframe, which overall makes it possible to position the preferred planesof polarization of the two lenses respectively, in a geometricallyaccurate manner with respect to the glasses, and in particular with asmall angular distance between the preferred planes of polarization ofthe two lenses, respectively.

The description above shows how it is possible, by overmolding, tointegrate in a lens the polarization function which is not accessible byinjection molding.

The present invention also relates to other functions, for example,infrared filtration, which are difficult to access by injection molding.This is because the known pigments which have infrared filtrationproperties are sensitive to heat and deteriorate when they are subjectedto the injection temperatures required by the processing of the injectedpolycarbonate (280 to 340° C.). The processing of these pigments inextruded polycarbonate makes it possible to form a sheet integratingthese pigments without reaching the maximum operating temperatures whichare about 200 to 250° C. This sheet can then be thermoformed in order toobtain the shape of the lens. During this thermoforming, the temperaturein the sheet does not exceed 200° C. The thermoformed sheet can then beovermolded. It is of course also possible to directly overmold the sheetin a flat blank.

This process makes it possible to create an insert to be overmolded in amaterial other than polycarbonate and the processing of which requireslow temperatures. The term “processing” also means obtaining an insertto be overmolded by an extrusion process, whether or not associated withthermoforming or even obtaining an insert by injection in a materialinjected at low temperatures. One condition to comply with is that thematerials retained for the insert and the matrix, generallypolycarbonate for the latter, have a compatibility which makes itpossible to guarantee good adherence of one on the other afterovermolding.

The process according to the invention also makes it possible to createan optical function in the region of the lens where the latter is used.Thus the photochromic function, which modifies the intensity of the lenscolor as a function of the received light intensity, can be obtained byincorporation of photochromic pigments in the injected material. Thesepigments are sensitive to heat and lose a lot of their efficiency whenthey are injected at the temperature of the polycarbonate. In addition,the quantity of pigments needed in order to properly achieve thisfunction is so large that it substantially affects (negatively) themechanical strength properties of the finished product to such an extentthat there is no further benefit in choosing polycarbonate as the basematerial. Finally, the effective proportion of pigments is very smallsince only the pigments present on the outer surface of the piece areactivated. The overmolding process is then totally adapted for thisphotochromic function.

Other functions again can be obtained by the process according to theinvention: obtaining coloration, a hard surface layer, specificfiltration (laser, infrared, shade, etc.), obtaining an antifog layer,etc.

Depending on the function which it is desired to obtain, the housingdesigned to receive the composite strip integrating this function can bemade on the convex face, as described above, or on the concave face ofthe blank.

A blank according to the invention can also be produced by anotherprocess than the overmolding process described by way of nonlimitingexample above. Thus, a blank according to the invention can be obtainedalso by adhesive bonding, by two-shot injection molding or by any otherprocess.

The overmolding process described above, or even adhesive bonding, allowthe use of substantially different materials for the composite strip andfor the matrix. These processes make it possible, for example, to employcellulose acetobutyrate which is beneficial to use with regard toheat-related stresses.

What is claimed is:
 1. A process for manufacturing a noncorrecting lensblank (1) integrating an optical function, having inner (2 c) and outer(2 b) faces which are respectively concave and convex, delimited by aperipheral border (2 a), and comprising a matrix (4) made of transparentmaterial, transmitting light from the outer face toward the inner face,and an insert (6) integrating the optical function, comprising:manufacturing the matrix (4) while at the same time making a housing (5)in one of the faces (2 b, 2 c) of the matrix (4), and fitting the insert(6) into the housing (5).
 2. The process for manufacturing a blankaccording to claim 1, wherein the housing (5) is sized to occupy themajority of the surface of the face (2 b, 2 c) of the matrix in whichthe housing is made.
 3. The process for manufacturing a blank accordingto claim 1, wherein the steps of making the housing (5) forms a bottomof the housing with a curvature substantially identical to that of theface (2 b, 2 c) in which the housing is produced.
 4. The process formanufacturing a blank according to claim 1, wherein the housing (5) ismade with a substantially constant depth.
 5. The process formanufacturing a blank according to claim 1, wherein: the step ofmanufacturing the matrix (4) forms the peripheral border (2 a) from twotruncated concentric circular edges (2 a 1) and (2 a 2), separated bytwo straight parallel edges (2 a 3, 2 a 4), and the step of making thehousing makes a perimeter (5 a) of the housing (5) with substantiallythe same profile as that of the peripheral border (2 a), and is fittedin a homothetic manner into the latter.
 6. The process of manufacturinga blank according to claim 1, wherein: the step of manufacturing thematrix (4) forms the peripheral border (2 a) predominantly circular, andthe step of making the housing makes a perimeter (5 a) of the housing(5) with two truncated concentric circular edges (5 a 1, 5 a 2),separated by two straight parallel edges (5 a 3, 5 a 4).
 7. The processfor manufacturing a blank according to claim 6, wherein: the step ofmanufacturing the matrix (4) forms the peripheral border (2 a) from apredominant circular part and a straight part (2 a 5), and the step ofmaking the housing (5) makes one of the straight edges (5 a 4)coincident with the straight part of the matrix.
 8. The process ofmanufacturing a blank according to claim 1, further comprising coveringthe outer face (2 b) of the blank with at least one layer of a materialchosen from the group comprising scratch-resistant materials, filteringmaterials and colored materials.
 9. The process for manufacturing ablank according to claim 1, wherein in producing the matrix (4) and thehousing (5) and the insert (6), the inner (2 b) and outer (2 c) faces ofthe blank (1) each have, at least in part, a symmetry of revolutionabout a same optical axis (7) determining an optical center (8) on theouter (2 b) and inner (2 c) faces of the blank (1).
 10. The process formanufacturing a blank according to claim 9, wherein in producing thematrix (4) and the housing (5) and the insert (6), the geometric shapeof the outer face (2 b) and the geometric shape of the inner face (2 c)are defined by two spheres of centers (8, 9) spaced out along theoptical axis (7).
 11. The process for manufacturing a blank according toclaim 9, wherein in producing the matrix (4), the peripheral border (2a) has at least in part a profile of revolution about a geometric center(10), placed at some distance and distinct from the optical axis (7).12. The process for manufacturing a blank according to claim 11, furthercomprising: producing the insert (6) in a polarizing material having apreferred plane of polarization, and making the housing (5) and fittingthe insert (6) into the housing (5) of the matrix so that the plane ofpolarization is substantially perpendicular or parallel to a planedefined by the optical axis (7) and the geometric center (10).
 13. Theprocess for manufacturing a blank according to claim 9, furthercomprising: producing the insert (6) in a polarizing material having apreferred plane of polarization, and making the housing (5) and fittingthe insert (6) into the housing (5) of the matrix so that the plane ofpolarization is substantially parallel to the optical axis (7) of theblank.
 14. The process for manufacturing a blank according to claim 12,wherein in a plane of section substantially parallel or perpendicular tothe preferred plane of polarization, a thickness of the blank decreasescontinually when moving away from the optical axis (7) toward theoutside.
 15. The process for manufacturing a blank according to claim 1,further comprising: producing the insert (6) in a polarizing materialhaving a preferred plane of polarization, and producing the housing (5)and fitting the insert (6) into the housing (5) of the matrix so thatthe plane of polarization is substantially parallel to a transverseplane (3) of the blank (1) thus obtained.
 16. The process formanufacturing a blank according to claim 15, further comprising: makingthe housing (5) with a perimeter (5 a) including two truncatedconcentric circular edges (5 a 1, 5 a 2), separated by two straightparallel edges (5 a 3, 5 a 4), and cutting the insert (6) in thepolarizing material such that the insert (6) has a shape complementaryto that of the housing and comprises two truncated circular andconcentric edges, separated by two straight parallel edges (5 a 3, 5 a4), in which a preferred plane of polarization is substantially parallelor perpendicular to the straight parallel edges of the insert.
 17. Theprocess for manufacturing a blank according to claim 1, furthercomprising overmolding the insert (6) in the housing (5).
 18. Theprocess for manufacturing a blank according to claim 1, furthercomprising adhesively bonding the insert (6) into the housing (5).
 19. Anoncorrecting lens blank integrating an optical function, having inner(2 c) and outer (2 b) faces, which are respectively concave and convex,delimited by a peripheral border (2 a), and comprising a matrix (4) madeof transparent material, transmitting light from the outer face towardthe inner face, and an insert (6) integrating the optical function,manufactured in compliance with the process according to claim
 1. 20. Anoncorrecting lens blank integrating an optical function, having inner(2 c) and outer (2 b) faces, which are respectively concave and convex,delimited by a peripheral border (2 a), and comprising a matrix (4) madeof transparent material, transmitting light from the outer face towardthe inner face, and an insert (6) integrating the optical functionplaced in one of the faces of the matrix, wherein the insert (6) has twotruncated concentric circular edges (5 a 1, 5 a 2), separated by twostraight parallel edges (5 a 3, 5 a 4).
 21. The noncorrecting lens blankaccording to claim 20, wherein the peripheral border (2 a) comprises twotruncated concentric circular edges (2 a 1, 2 a 2), separated by twostraight parallel edges (2 a 3, 2 a 4).
 22. The noncorrecting lens blankaccording to claim 21, wherein a straight edge of the insert (6) iscoincident with a straight edge of the peripheral border.
 23. Thenoncorrecting lens blank according to claim 20, wherein the peripheralborder (2 a) comprises a predominant circular part and a straight part(2 a 5).
 24. The noncorrecting lens blank according to claim 20, whereinthe insert (6) integrates a polarization function and has a preferredplane of polarization perpendicular or parallel to the straight edges ofthe insert (6).
 25. A pair of glasses (11) comprising a frame (12) andtwo noncorrecting lenses (13, 14) integrating an optical function andbeing supported by said frame, characterized in that each lens ismanufactured from a blank according to claim 19.